In a cancer cell, receptor tyrosine kinases (TK) play important role in connecting the extra-cellular tumor microenvironment to the intracellular signaling pathways that control diverse cellular functions, such as, cell division cycle, survival, apoptosis, gene expression, cytoskeletal architecture, cell adhesion, and cell migration.
The type I insulin like-growth factor receptor (IGF-1R, CD221) belongs to receptor tyrosine kinase (RTK) family, (Ulrich et al., Cell.; 61:203-12 (1990)). Insulin-like growth factors (IGFs), e.g., IGF-I and IGF-II have been implicated in the acquisition of an invasive and metastatic tumor phenotype [Baserga, Cell., 79:927-30 (1994); Baserga et al., Exp. Cell Res., 253:1-6 (1999) and Baserga et al., Int. J. Cancer., 107:873-77 (2003)]. There is a large body of literature on the actions and activities of IGFs (IGF-1, IGF-2, and IGF variants). See Van Wyk et al., Recent Prog. Horm. Res., 30: 259 (1974); Binoux, Ann. Endocrinol., 41: 157 (1980); Clemmons and Van Wyk, Handbook Exp. Pharmacol., 57: 161 (1981); Baxter, Adv. Clin. Chem., 25:49 (1986); U.S. Pat. No. 4,988,675; WO 91/03253; WO 93/23071). Each of these growth factors exerts its mitogenic effects by binding to a common receptor named the insulin-like growth factor receptor-1 (IGF-1R) (Sepp-Lorenzino, Breast Cancer Research and Treatment 47:235 (1998)); Klapper, et al., Endocrinol. 112:2215 (1983) and Rinderknecht, et al., Febs. Lett. 89:283 (1978)), which is closely related to the insulin receptor (IR) in structure and shares some of its signaling pathways (Jones and Clemmons, Endocr. Rev., 16: 3-34 (1995); Ulrich et al., Cell 61: 203 212, (1990)).
The molecular architecture of IGF-1R comprises, two extra-cellular α subunits (130-135 kD) and two membrane spanning β subunits (95 kD) that contain the cytoplasmic catalytic kinase domain. IGF-1R, like the insulin receptor (InsR), differs from other RTK family members by having covalent dimeric (α2β32) structures. Structurally, IGF-1R is highly related to InsR (insulin receptor) (Pierre De Meyts and Whittaker, Nature Reviews Drug Discovery.; 1: 769-83 (2002); Ulrich et al., EMBO J., 5:2503-12 (1986); Blakesley et al., Cytokine Growth Factor Rev., 7:153-56 (1996)). Insulin-like growth factor-I (IGF-I) is a 7649-dalton polypeptide with a pI of 8.4 that circulates in plasma in high concentrations and is detectable in most tissues (Rinderknecht and Humbel, Proc. Natl. Acad. Sci. USA, 73: 2365 (1976); Rinderknecht and Humbel, J. Blol. Chem., 253: 2769 (1978)). The binding of IGF-1 and IGF-2 to the a chain induces conformational changes that result in auto-phosphorylation of each β-chain at specific tyrosine residues, converting the receptor from unphoshorylated state to the active state. The activation of three tyrosine residues in the activation loop (Tyr residues at 1131, 1135 and 1136) of the kinase domain leads to increase in catalytic activity that triggers docking and phosphorylation of the substrates such as IRS-1 and Shc adaptor proteins. Activation of these substrates leads to phosphorylation of additional proteins involved in the signaling cascade of survival (PI3K, AKT, TOR, S6) and/or proliferation (mitogen-activated protein kinase, p42/p44) (Pollak et al., Nature Reviews Cancer.; 4:505-516 (2004); Baserga et al., Biochem Biophys Act.; 1332:F105-F126 (1997); Baserga et al, Int. J. Cancer.; 107:873-77 92003)).
There is considerable evidence for a role for IGF-I and/or IGF-IR in the maintenance of tumor cells in vitro and in vivo (Baserga, Cancer Res., 55:249-252 (1995); for a review, see Khandwala et al., Endocr. Rev. 21: 215-244 (2000)); Daughaday and Rotwein, Endocrine Rev., 10:68-91 (1989); Sell C. et al., Proc. Natl. Acad. Sci., USA, 90: 11217-11221 (1993); Sell C. et al., Mol. Cell. Biol., 14:3604-3612 (1994); Morrione A. J., Virol., 69:5300-5303 (1995)). For example, individuals with “high normal” levels of IGF-I have an increased risk of common cancers compared to individuals with IGF-I levels in the “low normal” range (Rosen et al., Trends Endocrinol. Metab. 10: 136-41, 1999). For a review of the role IGF-I/IGF-I receptor interaction plays in the growth of a variety of human tumors, see Macaulay, Br. J. Cancer, 65: 311 320, (1992). Overexpression of IGF-1R has also been demonstrated in several cancer cell lines and tumor tissues—IGF-1R is overexpressed in 40% of all breast cancer cell lines (Pandini, et al., Cancer Res.; 5:1935 (1999)) and in 15% of lung cancer cell lines. In breast cancer tumor tissue, it is overexpressed 6-14 fold. Likewise, ninety percent of colorectal cancer tissue biopsies exhibit elevated IGF-1R levels, wherein the extent of IGF-1R expression is correlated with the severity of the disease. Analysis of primary cervical cancer cell cultures and cervical cancer cell lines revealed 3- and 5-fold overexpression of IGF-1R, respectively, as compared to normal ectocervical cells (Steller, et al., Cancer Res.; 56:1762 (1996)). Expression of IGF-1R in synovial sarcoma cells also correlated with an aggressive phenotype (i.e., metastasis and high rate of proliferation; Xie, et al., Cancer Res.; 59:3588-9 (1999)).
Other arguments in favor of the role of IGF-IR in carcinogenesis come from studies using murine monoclonal antibodies directed against the receptor or using dominant negative forms of IGF-IR. In effect, murine monoclonal antibodies directed against IGF-IR inhibit the proliferation of numerous cell lines in culture and the growth of tumor cells in vivo ([Arteaga C. et al., Cancer Res.; 49:6237-6241 (1989); Li et al., Biochem. Biophys. Res. Com.; 196:92-98 (1993); Scotlandi K et al., Cancer Res., 58:4127-4131 (1998)0. Likewise, Jiang et al., Oncogene, 18:6071-6077 (1999) has demonstrated that a negative dominant of IGF-IR is capable of inhibiting tumor proliferation.
IGF-1R-specific antibodies are described in one or more of the following publications—WO 2003/100008); WO 2002/53596; WO 2004/71529); WO 2003/59951); WO 2004/83248); WO 2003/106621); WO 2004/87756). See also Burtrum et. al. Cancer Research 63:8912-8921 (2003).
In years past, IGF-IR has become an attractive molecular target for cancer treatment given as it is expressed in a wide range of tumors (Renato Baserga, Experimental Cell Research, 315: 727-732 (2009). Several studies indicate that IGF-IR activation is associated with the growth, invasion, and metastasis of breast cancer including the observation that the expression of constitutively active IGF-IR in the mammary gland leads to the development of tumors while overexpression of a constitutively activated IGF-IR is sufficient to cause transformation of immortalized human mammary epithelial cells and growth in immunocompromised mice. Emerging data suggest that IGF-IR signaling is important for the development of breast tumors and cancers continue to depend upon this pathway for sustained growth and survival (Ryan et al., The emerging role of the insulin-like growth factor pathway as a therapeutic target in cancer.; Oncologist; 13:16-24 (2008).
The IGF-IR pathway is also implicated in resistance to targeted therapies including those that target the ER and the epidermal growth factor receptor (EGFR) family members EGFR and HER2. For example, IGF-IR is reportedly up-regulated during the acquisition of tamoxifen resistance. According to published data, continuous exposure of MCF-7 cells to tamoxifen resulted in the eventual emergence of resistant cells, called MCF-7 Tam-R, which use IGF-IR for their growth (Knowlden et al., Insulin-like growth factor-I receptor signaling in tamoxifen-resistant breast cancer: a supporting role to the epidermal growth factor receptor.; Endocrinology; 146:4609-18 (2005). Likewise, activation of the IGF-IR signaling cascade has also been reported in models of resistance to agents that target the EGFR family. Jennifer H. Law; Cancer Research 68: 10238 (2008), doi: 10.1158/0008-5472.CAN-08-2755; Jones et al.; Endocr. Relat. Cancer; 11:793-814 (2004).; Lu Y et al., Insulin-like growth factor-I receptor signaling and resistance to trastuzumab (Herceptin).; J Natl Cancer Inst; 93:1852-7 (2001)0 As a consequence, use of IGF-1R pathway inhibitors appears to be justified in order to prevent or attenuate the development of resistance. See Jennifer Law, supra; Knowlden et al., Breast Cancer Res Treat, 111:79-91 (2008)).
Agents, such as those noted supra, are expected to decrease IGF-1R function and/or expression and thus may be effective in treating patents presenting with IGF-1R mediated pathologies. However, it is expected that a portion of cancer patients may not respond to such treatments or may need to be monitored over time while being treated with an IGF-1R inhibitor.
As a consequence, there is a need in the art for methods for not only identifying specific cancer populations likely to present with or at risk of developing an IGF-1R pathology but also a need for predicting a patient's probable outcome to treatment with or response to one or more anti-cancer therapies that target IGF-1R, e.g., sensitivity or resistance to treatment with an IGF-1R inhibitor.
In the past decade, LKB1 (STK11) has generated significant interest especially when studies showed that it is defective in patients with Peutz-Jeghers syndrome (PJS). Specifically, inactivating mutations, exonic deletions and whole gene deletions in Lkb1 were found in most PJS syndrome patients. [Hezel et al., Oncogene; 27: 6908-6919 (2008); Volikos et al.; J Med Genet; 43: e18 (2006); WO/2009/102986.] The type and pattern of these mutations have been extensively reviewed elsewhere. [Alessi et al., Annu Rev Biochem 75: 137-163 (2006); Launonen V., Hum Mutat.; 26: 291-297 (2005).] PJS is characterized by; (1) muco-cutaneous hyperpigmentation involving the lips and hands, (2) the early development of hamartomas, which are well-differentiated vascular polyps found throughout the gastrointestinal tract beginning at an early age and (3) an increased incidence of carcinomas [Westerman et al., Lancet 353: 1211-1215 (1999)]. Researchers have identified more than 140 mutations in the LBK1 gene that are responsible for Peutz-Jeghers syndrome. Many of these mutations result in the production of an abnormally short, nonfunctional version of the serine/threonine kinase 11 enzyme. Other mutations change a single protein building block (amino acid) used to build the enzyme. Research has shown that the loss of this enzyme's function allows cells to divide too often, leading to the formation of polyps in the gastrointestinal tract. Sometimes these polyps develop into malignant (cancerous) tumors. Among the most important associated health-related concerns is the increased risk of cancer development Sanchez-Cespedes M., Oncogene; 26:7825-7832 (2007). While gastrointestinal tumors are the most commonly diagnosed malignancies in PJS patients, the risk of developing cancer from other origins is also significantly higher. [Sanchez-Cespedes M supra; A Hemminki., Cell. Mol. Life Sci.; 55: 735-750 (1999)].
LKB1 is a ubiquitously expressed gene, which encodes a serine/threonine kinase. There is only a single isoform of the LKB1 gene in the human genome, which spans 23 kb and is made up of nine coding exons and a final noncoding exon. The LKB1 gene maps to the chromosomal region 19p13.3, which is frequently lost in several types of cancer. The gene is transcribed in a telomere-to-centromere direction and encodes for a protein of 433 amino acids and approximately 48 kDa (Hemminki et al., Nature 391, 184-187 (1998)]. The protein possesses a nuclear localization signal in the N-terminal noncatalytic region (residues 38-43) and a kinase domain (residues 49-309) [Alessi et al., Annu Rev Biochem 75: 137-163 (2006)]. A putative prenylation motif (CAAX-box) is located within the C-terminus. [Launonen V., Hum Mutat 26: 291-297 (2005); Alessi, supra]. Although LKB1 protein expression is mainly cytoplasmic, it can also be localized in the nucleus. LKB1 is a master kinase that activates a family of 14 kinases related to AMPK [adenosine monophosphate (AMP)-activated protein kinase] suggesting that it may contribute to tumorigenesis and metastasis through mechanisms other than AMPK regulation (Hemminki, supra).
A review of the literature informs of a total of 40 different somatic LKB1 mutations in 41 sporadic tumors and seven cancer cell lines. Most of the somatic LKB 1 mutations result in truncation of the protein. The loss of the enzyme's tumor suppressor function likely underlies the increased risk of gastrointestinal tumors, breast cancer, and other forms of cancer in PJS patients. Mutations occur particularly in lung and colorectal cancer. Of significant import is the observation that PJS patients are at an increased risk of developing malignancies in epithelial tissues—for example it has been estimated that there is about 84, about 213 and about 520 fold increased risk of developing colon, gastric and small intestinal cancers respectively. PJS patients are also at an increased risk of developing cancers in the breast, lung, ovaries, uterus, cervix and testes. To date, 144 different mutations in LKB1 have been identified in PJS patients and sporadic cancers, [Alessi, supra.] Somatic mutations in LKB1 are observed in sporadic pulmonary, pancreatic and biliary cancers and melanomas. [A F Hezel, Oncogene 27, 6908-6919 (2008)]. Individuals with PJS are also at increased risk for intestinal and extraintestinal malignancies. Colorectal and gastric cancers can arise from adenomas that are commonly found in individuals with PJS. The risk for pancreatic cancer is also greatly increased over the population risk [Giardiello et al., N Engl J Med.; 316: 1511-4 (1987). The same holds true for neuroendocrine lung cancers. [Amin et al., Pathol Int; 58: 84-88 (2008)].
Recent studies have demonstrated that loss of LKB1 is associated with invasiveness and metastasis in breast, lung, and endometrial adenocarcinomas [Zhao et al.; Cancer Cell. 3:483-495 (2003); Contreras et al., Cancer Res. 68:759-766 (2008)]. For example, LKB1 is one of the most commonly mutated genes in sporadic human lung cancer, particularly in multiple subtypes of non-small cell lung carcinoma (NSCLC), where at least 15 to 35% of cases have this lesion. [Sanchez-Cespedes M, et al., Cancer Res.; 62:3659-3662 (2002); David B. Shackelford, Nature Reviews Cancer 9:563-575 (2009); Ji, H. et al., Nature 448:807-810 (2007).]. The mutational pattern of LKB1 in lung tumors of sporadic origin is that of a classical tumor-suppressor gene. First of all, mutations are homozygous, as predicted by Knudson's two hit hypothesis. Second, a large proportion of mutations lead to the generation of truncated proteins, indicative of an inactivating event. Third, the mutations in tumors of sporadic origin arise somatically, and so are only present in the tumor tissue. See Sanchez-Cespedes M., Oncogene, 26:7825-7832 (2007) for a list of the alterations found in LKB1 relative to lung cancer.
The data also show that LKB1 is somatically mutated in 20% of cervical carcinomas, making it the first known recurrent genetic alteration for this tumor type. [Wingo et al., PLoS ONE 4(4): e5137. (2009); doi:10.1371/journal.pone.0005137; Robert Shaw; Sci. Signal., 2:pe55 (2009)]. Females with PJS are also at risk for ovarian sex cord tumors with annular tubules (SCTAT), mucinous tumors of the ovaries and fallopian tubes and adenoma malignum of the cervix, a rare aggressive cancer. Males occasionally develop calcifying Sertoli cell tumors of the testes, which secrete estrogen and can lead to gynecomastia. [Young et al., Mod Pathol.; 2: S81-98 (2005).]
LKB1 promoter hypermethylation has been reported in nearly 50% of sporadic papillary breast cancers and 12% of testicular cancers, whereas LKB1 promoter hypermethylation appears uncommon or absent in other types of sporadic breast cancers, as well as colon, gastric and pancreatic cancers [Esteller et al., Oncogene; 19: 164-168 (2000)]. Additionally, loss of LKB1 expression has been noted in sporadic endometrial cancers as well. [Contreras et al.; Cancer Res 68: 759-766 (2008)].
Cancer as a disease contributes to a major financial burden to the community and to individuals. It accounts for nearly one-quarter of deaths in the United States, exceeded only by heart diseases. Although conventional histological and clinical features have been correlated to prognosis, the same apparent prognostic type of tumor varies widely in its responsiveness to therapy and consequent survival of the patient. In addition, accurate prognosis as well as a determination of treatment outcome vary broadly across most cancer types.
As a consequence, a great deal of effort is being directed to using new technologies to find new classes of biomarkers, which is becoming one of the highly prized targets of cancer research. See Petricoin et al, Nature Reviews Drug Discovery, 1: 683-695 (2002); Sidransky, Nature Reviews Cancer, 2: 210-219 (2002). Accompanying the increased knowledge about biomarkers is an increased appeal of the use of biomarkers as predictive or risk assessment entities. Scientists believe that the development of new validated risk-assessment biomarkers will lead to significant reductions in healthcare and drug development costs as well as provide a tool for achieving successful preventive intervention. Within clinical research, oncology is expected to have the largest gains from biomarkers over the next five to ten years. Development of personalized medicine for cancer is closely linked to biomarkers, which may serve as the basis for diagnosis, drug discovery and monitoring of diseases. Jain K K. Curr Opin Mol Ther. 2007 December; 9(6):563-71 (2007).
However, the ability to predict drug sensitivity in patients is particularly challenging especially in IGF-1R mediated disorders because the extensive histoclinical heterogeneity attendant such cancers often times cause differential response to anti-cancer drugs, thus resulting in a diversity of chemosensitivity in cancer cells.
Examples of biomarkers include genetic markers (e.g., nuclear aberrations [such as micronuclei], gene amplification, and mutation), cellular markers (e.g., differentiation markers and measures of proliferation, such as thymidine labeling index), histologic markers (e.g., premalignant lesions, such as leukoplakia and colonic polyps), and biochemical and pharmacologic markers (e.g., ornithine decarboxylase activity). The first demonstration of molecular signatures in oesophageal cancer that correlate with treatment response is detailed in Luthra, R. et al.; Gene expression profiling of localized esophageal carcinomas: association with pathologic response to preoperative chemoradiation.; J. Clin. Oncol. 12 Dec. 2005 (10.1200/jco.2005.03.3688).
Other studies have used gene expression profiling to analyze various cancers, and those studies have provided new diagnosis and prognosis information in the molecular level. See Zajchowski et al.,—‘Identification of Gene Expression Profiled that Predict the Aggressive Behavior of Breast Cancer Cells,” Cancer Res. 61:5168 (2001); West et al, “Predicting the Clinical Status of Human Breast Cancer by Using Gene Expression Profiles,” Proc. Natl. Acad. Sc. U.S.A. 98:11462 (2001); van't Veer et al., “Gene Expression Profiling Predicts the Outcome of Breast Cancer,” Nature 415:530 (2002); Roberts et al., “Diagnosis and Prognosis of Breast Cancer Patients,” WO 02/103320; Sorlie et al, Proc. Natl. Acad. Sc U.S.A. 100:8418 (2003); Perou et. al., Nature 406:747 (2000); Khan et al, Cancer Res 58, 5009 (1998); Golub et al, Science 286, 531 (1999); Alizadeh et al, Nature 403, 503 (2000). Methods for the identification of informative genesets for various cancers have also been described. See Roberts et al., “Diagnosis and Prognosis of Breast Cancer Patients,” WO 02/103320; Golub et al, U.S. Pat. No. 6,647,341.
Current predictive and prognostic biomarkers include DNA ploidy, S-phase, Ki-67, Her2/neu (c-erb B-2), p53, p21, the retinoblastoma (Rb) gene, MDR-1, bcl-2, cell adhesion molecules, blood group antigens, tumor associated antigens, proliferating antigens, oncogenes, peptide growth factors and their receptors, tumor angiogenesis and angiogenesis inhibitors, and cell cycle regulatory proteins. Beta human chorionic gonadotropin (J3-hCG), carcinoembryonic antigen, CA-125, CA 19-9, and others have been evaluated and shown to correlate with clinical response to chemotherapy. See de Vere White et al., Oncology, 12(12):1717-23 (1998); Stein, J. P. et al., “Prognostic markers in bladder cancer: a contemporary review of the literature” J. Urol.; 160 (3 Pt 1):645-59 (1998); Cook, A. M. et al., “The utility of tumour markers in assessing the response to chemotherapy in advanced bladder cancer” Proc. Annu. Meet. Am. Soc. Clin. Oncol., 17:1199 (1998).
In the case of cancer, molecular markers such as the level of HER2/neu, p53, BCL-2 and estrogen/progesterone receptor expression have been clearly shown to correlate with disease status and progression. This example demonstrates the value of diagnostic and prognostic markers in cancer therapy. Reports from retrospective studies have shown that multivariate predictive models combining existing tumor markers improve cancer detection. See van Haaften-Day C. et al., “OVX1, macrophage-colony stimulating factor, and CA-125-II as tumor markers for epithelial ovarian carcinoma: a critical appraisal”, Cancer (Phila), 92: 2837-44, (2001). These findings bring hope that cancer treatment will be vastly improved by better predicting the response of individual tumors to therapy.
Consequently, while a central paradigm in the care and treatment of patients presenting with cellular proliferative disorders mediated by IGF-1R is to offer better risk assessment, screening, diagnosis, prognosis and selection and monitoring of therapy, the current state of art, nevertheless, paints a grim picture relative to prognostic biomarkers useful for tailoring a therapeutic protocol involving an IGF-1R inhibitor (IGF-1Ri). The identification of predictive biomarkers is thus an essential precondition for the further development of personalized medicine The term biomarker refers not only to biological parameters measured directly from clinical diagnosis, gene diagnostics, etc., but also computation methods which allow for predictions to be made from suitable measured values of biological parameters, or make it possible to calculate a prognosis for the clinical response to a therapy. As indicated elsewhere, the finding of such complex biomarkers in practice is often extremely unreliable or even impossible owing to the great variety of possible biological parameters, which often exceeds significantly the number of subjects in clinical studies.
Previous studies have reported on the expression of IGF1-R, phospho-IGF-IR, insulin receptor substrates-1 (IRS1), and -2 (IRS2), and predictive gene expression signatures. See, for example, Cao et al., Cancer Res, 68:8039-48 (2008), Huang F et al., The mechanisms of differential sensitivity to an insulin-like growth factor-1 receptor inhibitor (BMS-536924) and rationale for combining with EGFR/HER2 inhibitors. Cancer Res.; 69:161-70 (2009); Byron et al., Insulin receptor substrates mediate distinct biological responses to insulin-like growth factor receptor activation in breast cancer cells. British J. Cancer; 95:1220-8 (2006). Thus, while insulin-like growth factor-1 receptor (IGF-1R), epidermal growth factor receptor (EGFR), and HER2 expressions have been reported to correlate with clinical outcomes in several solid tumors, the clinical significance of these biomarkers remains unclear. Indeed as late as 2007, investigators have argued for a better understanding of the clinical implications of risk assessment or prognostic biomarkers; e.g., predicting sensitivity of IGF-1R expressing cells to an IGF-1R inhibitor. See for example Matsubara et al., Journal of Clinical Oncology, 2007 ASCO Annual Meeting Proceedings (Post-Meeting Edition); 25 (18S); 4539 (2007), whose work suggests that IGF-1R expression in surgical gastric cancer specimens may predict poor outcomes in postoperative patients with gastric cancer. (emphasis supplied). Similar conclusions have been reached by other investigators relative to predicting treatment response to an IGF-1R inhibitor. Similarly, Zha J et al. provide an intriguing report detailing a comprehensive preclinical evaluation of predictive biomarkers for h10H5 (Genentech, South San Francisco, Calif.), a humanized monoclonal antibody to IGF-IR. Lead investigators argue that the identification of such biomarkers remains arguably the most important issue in development of drugs targeting IGF-IR. [Molecular predictors of response to a humanized anti-insulin-like growth factor-I receptor monoclonal antibody in breast and colorectal cancer. Mol Canc Ther 2009; 8:2110-21 (2009).]
In sharp contrast, Carden et al., Predictive biomarkers for targeting insulin-like growth factor-I (IGF-I) receptor; Mol. Cancer. Ther., 8: 2077 (2009) provide a detailed assessment of certain elements of the pathway limited to breast and colorectal cancer models, wherein the authors conclude that for sensitivity to h10H5 their data suggested that IGF2, IRS1, and IRS2 protein expression may be important for patient selection. (Emphasis supplied).
In yet another study, investigators have tried to correlate sensitivity of NSCLC cell lines to treatment with a specific IGF-1R antibody-designated R1507 (RO4858696—a fully human IgG1 monoclonal antibody directed against the extracellular portion of the human IGF-1R). Gong et al. report on their attempts to establish the sensitivity to R1507 of 22 NSCLC cell lines, which included 12 adenocarcinomas, 9 squamous cell carcinomas and 1 large cell carcinoma, each of which was examined for known EGFR/KRAS/NRAS/HRAS/PI3K mutations. According to the publication, sensitivity was assessed using a growth inhibition assay that measures a colorimetric signal produced by conversion of resazurin to resorufin, which apparently is directly proportional to the numbers of viable cells. Therein, the authors admit that none of the lines displayed “high sensitivity”. The instruction continues that the investigators were unable to calculate the concentration of drug needed to inhibit tumor growth by 50% (GIso) for each line. The instruction continues that the data failed to demonstrate correlation between R1507 sensitivity and lung cancer histology or mutation status. [PLoS One. 2009; 4(10): e7273; “High Expression Levels of Total IGF-1R and Sensitivity of NSCLC Cells In Vitro to an Anti-IGF-1R Antibody (R1507)].
Various attempts in evaluating IGF-1R protein expression in primary tumors from surgically treated NSCLC patients as a potential correlative biomarker utilizing IGF-1R inhibitors have also been described with inconclusive results. For example, Dziadziuszko et al., evaluated IGF1-R expression in tissue microarrays by immunohistochemistry (IHC). The authors discovered that while IGF-1R protein expression was higher in SCC squamous cell carcinomas (SCC), the expression levels of IGF-1R did NOT associate with survival although high IGF-1R gene copy number appeared to associates with better prognosis in operable NSCLC. [Journal of Clinical Oncology, 27 (15S): 7524 (2009)]. That IGF-1R expression, determined at the protein level using IHC staining does not represent a prognostic factor in resected NSCLC patients is also evident from studies conducted by F. Cappuzzo et al., Annals of Oncology Advance Access published online on Sep. 18, 2009; Annals of Oncology, doi:10.1093/annonc/mdp357.
In light of the above discussion, it is also clear that the art has, so far, failed to appreciate using expression levels of LKB1 as a potential prognostic biomarker useful for tailoring a therapeutic protocol involving an IGF-1R inhibitor.
Taken together, these deficiencies in the art creates a continuing need for innovative strategies that can better predict a patient's sensitivity to treatment or therapy with an IGF-1R inhibitor and inability to tolerate certain medications or treatments. Further, the pre-selection of patients who are likely to respond well to a medicine, drug, or combination therapy may reduce the number of patients needed in a clinical study or accelerate the time needed to complete a clinical development program (M. Cockett et al., Current Opinion in Biotechnology, 11:602-609 (2000)).
In sum, new biomarkers for predicting chemosensitivity to IGF-1R inhibitors are highly sought after to improve the current clinical capabilities of IGF-1R inhibitors. Accurate prognosis as well as a determination of treatment outcome with current IGF-1R inhibitors will eventually allow an oncologist to tailor the administration of therapy with patients having poorer prognoses being given the most aggressive treatment. Accurate prediction of treatment outcome, favorable or poor prognosis will also impact clinical trials for new cancer therapies, because potential study patients could then be stratified according to prognostic biomarkers. Further, the pre-selection of patients who are likely to respond well to an IGF-1R inhibitor mono or combination therapy also may reduce the number of patients needed in a clinical study or accelerate the time needed to complete a clinical development program (M. Cockett et al., Current Opinion in Biotechnology, 11:602-609 (2000)).
The present invention aims at overcoming the above deficiencies by providing clinically relevant prognostic tools useful in correlating a patient's response to a chemotherapeutic agent able to modulate IGF-1R signaling as well as identifying patients at risk of failing a therapeutic regimen/protocol involving an IGF-1R inhibitor. Towards this end, the present invention identifies a particular biomarker whose profile may be used in a clinical setting including predicting the patients treatment outcome with an IGF-1R targeted therapy. Indeed, it is demonstrated in the examples appearing hereunder that the expression profile of the biomarker is predictive of treatment with an IGF-1R inhibitor, alone or in combination with another therapeutic agent.